Traditionally, as shown in FIG. 1, an electric level conversion circuit 11 converts a high level VC1 with a maximum amplitude 3.3V, which is outputted from a logic controller 12, to a high level VC2 with a maximum amplitude 5.5V, and then outputs VC2 to a high level input terminal Signal of an electronic device 10, in order to turn on the electronic device 10. When the logic controller 12 outputs a low level, the electronic device 10 is turned off. In FIG. 1, a ground terminal GND of the electronic device 10 is grounded, the ground denoted as Gnd. However, the electric level conversion circuit only generates, at maximum, a high level with an amplitude 5.5V, whereas a high level used for turning on some electronic devices is higher than 5.5V, so the electric level conversion circuit may not successfully turn on these electronic devices.